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Uglie poles are debarked, but are not peeled smooth. This leaves a rough finish from the natural nodal swelling along the pole. By not peeling the pole smooth, more of the wood’s natural strength is retained. The rough surface is also ideal for TTT Ground Improvement as it allows the pole to interact better with the surrounding soil.
SED poles are peeled while still retaining the natural taper of the log, which leaves a smooth finish. This is suitable for suspended floors or retaining walls where the pile is visible after installation. The smooth surface is ideal for TTT Deep Piles as it minimises negative skin friction from the surrounding soil.
UniLog poles are machined to a uniform diameter, resulting in a very consistent machined finish. This is suitable for structural applications above the ground where the entire pole may be visible. It also allows brackets to be easily designed for the pole as the diameter is accurately known.
MultiPoles are any of the Uglie poles, SED poles, or UniLog poles, but with a hollow-core.
Each of these pole types can be treated to H5 (or H6 for marine applications) and produced from high density radiata pine.
Small End Diameter. It is the industry standard for grading timber poles. Due to the natural taper of the pole (average of 6mm/m) there will always be a small end and a large end with different diameters.
The hole is made by removing the corewood from the pole. Corewood doesn’t provide any structural strength to the pole, so removing it doesn’t reduce the strength of the pole.
The hole allows treatment chemicals to penetrate the pole from both the outside surface and from the inside, giving full penetration of the pole, which in turn increases strength and durability.
The hole allows the pole to shrink over time as it dries, while minimising the checking that can occurs along its length – this is very useful for visual applications.
The hole also allows multiple pole lengths to be joined together using TTT MultiPole Connectors (simple pin connectors) to achieve required depths, as opposed to handling extremely long poles supplied in a single piece. This is especially useful where the required depth is not accurately known, or where there is restricted space to work within. Poles can be joined until the required depth is reached. The ability to join poles also reduces waste.
The hole significantly lightens the pole. This allows trucks and rail wagons to carry much greater loads of poles at a time, with limitations being based on volume rather than weight, which is often the case with solid poles.
The hole can house a water jetting nozzle and hose to enable water jetting during installation, and can prevent hydraulicing during pile driving.
The hole allows structural components made from the poles to be post-tensioned with a reinforcing rod through the core.
The hole can also be filled with concrete to provide a composite element, with the strength and ductility of the outer wooden layer combined with the strength of the concrete core.
The hole can be used to grout a reinforcing rod down the pile to tie it to a slab or other structural components above.
The smooth surface of SED poles minimises the negative skin friction of the surrounding soil on the pile.
During a seismic event, liquefiable soils tend to settle. As they do, they pull downwards on anything that is within the soil, such as a pile. This is called negative skin friction. When piles experience too much negative skin friction they can buckle, break, or fail in other ways. When a pile has a smooth surface, negative skin friction is minimised. The pile’s smooth surface reduces the grip that soil can have on it, thus reducing the soil’s ability to pull the pile down.
Improving the ground relies on interaction between the soil and piles to stop the soil from liquefying during a seismic event. The rough surface of Uglie poles maximises their interaction with surrounding soils.
The consistent machined finish of UniLog poles is aesthetically-pleasing, while the accurately known diameter enables the easy design and installation of brackets.
No. During the treatment process the chemicals are chemically fixed to the wood fibres at the molecular level, preventing leeching over time.
PS stands for Producer Statement. These are documents that the professionals working on your project will supply at various stages along the way.
A PS1 accompanies a specific design by an engineer.
A PS2 is a peer review of an engineer’s design. For most residential designs it is not needed. Also note that specific designs by engineers are not automatically required to be accompanied by PS2 documentation.
A PS3 is provided by the contractor that completes the work on site.
A PS4 is a construction review by the engineer, and is carried out during construction. Commonly referred to as "engineers sign off,” it indicates that the engineer is happy with how the installation was carried out by the contractor. It normally involves one or more site inspections by the engineer during construction and possibly verification testing of some sort (E.G. testing pile sets).
Each of these methods is a way for an engineer to test the load capacity of the piles during construction. This enables the engineer to verify that piles are meeting the loads required by the design. These methods vary in accuracy and cost.
Testing pile sets involves dropping a weight onto a pile (E.G. 1000kg weight with a 1.0m drop) and measuring the sets (how far the pile moves with each blow). Generally the sets are in the region of 5-20mm, but this can vary according to each site. The Hiley Formula then enables an engineer to calculate the load capacity based on the pile sets. Testing pile sets in this manner is generally acceptable for residential buildings.
A Pile Driving Analyser (or PDA) is an electronic device that has sensors which are mounted on the pile being tested. When a weight is dropped on the pile (similar to testing pile sets) the PDA tester assesses the load capacity of the pile. PDA provides more accuracy and information than the Hiley Formula, and is generally used on commercial buildings.
Static load testing involves placing a lot of weight on the pile being tested, then measuring how far the pile moves at specified intervals over several hours.
300mm. For sites with more than 300mm lateral movement, an in-ground retaining wall may be considered to reduce the lateral movement to within the threshold of timber piles.
If a suitable bearing layer is identified (of sufficient hardness and thickness), deep piles are suitable. An enhanced slab should be designed to be supported directly on top of the piles. If the site contains sloping ground and/or elevated floor level requirements (due, for example, to flood levels) then a suspended concrete slab is an option.
Alternatively, a ground improvement system using timber piles can be designed to improve the ground to TC2 levels. On top of the improved ground a load transfer platform can be constructed, followed by a TC2 waffle slab.
Not usually. If we have to we use a concrete layer, so it is always more economical if they work directly for you.
If a suitable bearing layer is identified (of sufficient hardness and thickness) then TTT Deep Piles Foundations are suitable. Alternatively, a TTT Raft Foundation (which is equivalent to a Type 2B surface structure, but requires 100kPa or less with specific design) is usually suitable.
Bearers and joists can be designed to sit above either of these foundation types. These can be in accordance with NZS 3604, or according to specific design.
No. A geotechnical report is very useful as a factual report of the ground conditions, and the recommendations within the report are useful to provide some guidance. However, they are just recommendations and an engineer who performs specific engineering design for a foundation, along with an accompanying PS1 and justification for their foundation, is the one who signs off and takes liability for that design, not the author of the geotechnical report.
The expected level of land damage following a future seismic event (TC1 expecting the least damage through to TC3 expecting the most damage). Subsequently, the level of engineering required for new foundations in each of these categories increases.
TC1, TC2, and TC3, with specific engineering design.
Subject to how the design was carried out, the verification testing can vary from nothing (if the engineer is satisfied after watching some of the piles being driven), to geotechnical tests such as Cone Penetration Test or Dilatometer testing after all the piles have been installed.
For poles in the ground, even close to a river or ocean, and below the water table, H5 treatment is sufficient. For poles in a marine environment, such as in a lake supporting a jetty, H6 treatment is required.
The geotechnical report provides most of the information as to what our options are or are not, along with a few extra details such as the desired floor type (timber or concrete) and floor level requirements due to flooding.
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Yes, get in touch with your information.
Yes, get in touch with us today and we’ll get things started.
Everyone in the process – from home owners, to building companies, to insurance companies.
TTT foundations are installed using a specialised High Frequency Vibration system. Our contractors use custom-built machinery that operates at an exceptionally finely tuned frequency. This method ensures minimal product damage, and doesn’t disturb neighbouring properties.
We can do if required. However, we do most of our jobs with High Frequency Vibration as it is fast, efficient, and leaves surrounding properties undisturbed.
No, we do both commercial and residential work, as well as retaining walls and bridges.
We sure can – get in touch with the information and we can take it from there.
A Site-Specific Safety Plan (SSSP) is produced for each site following a check of all hazards applicable to each site. If we are working as a subcontractor on someone else’s site we will follow the safety processes they have in place in addition to our own.
Yes. An example is the use of our Ground Improvement system on a causeway upgrade project in Auckland. Read more about it here.